The Citroen K1H (TU3A) is a 1,124 cc, inline-three petrol engine produced between 1993 and 2001. Part of the PSA TU engine family, it delivers economical performance for compact city cars. Equipped with a single overhead camshaft (SOHC) and multi-point fuel injection, it produces 45 kW (61 PS) with 93 Nm of torque, offering light and responsive urban driving characteristics.
Fitted primarily to the Citroën Saxo and Peugeot 106, the K1H (TU3A) was engineered for low running costs, ease of maintenance, and compact packaging. Emissions compliance was achieved through a three-way catalytic converter and lambda feedback control, meeting Euro 2 standards across its production run. Its lightweight design and low friction internals contribute to strong fuel economy in stop-start conditions.
One documented concern is premature camshaft wear observed in certain 1993–1996 production units, highlighted in PSA Technical Bulletin TGB004. This issue is attributed to marginal oil flow design in early cylinder heads. From 1997 onward, revised oil gallery machining and upgraded camshafts were implemented to resolve the issue.
Production years 1993–2001 meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/7890).
The Citroen K1H (TU3A) is a 1,124 cc inline-three petrol engine engineered for compact city cars (1993–2001). It combines SOHC 12-valve architecture with multi-point fuel injection to deliver efficient, lightweight performance. Designed to meet Euro 2 emissions standards, it prioritizes fuel economy and mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,124 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-3, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 84.8 mm | |
| Power output | 45 kW (61 PS) @ 5,800 rpm | |
| Torque | 93 Nm @ 3,000 rpm | |
| Fuel system | Multi-point fuel injection (Siemens SIM1K) | |
| Emissions standard | Euro 2 | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (interval: 90,000 km or 6 years) | |
| Oil type | SAE 10W-30, ACEA A1/A2 | |
| Dry weight | 88 kg |
The naturally aspirated SOHC design provides predictable, low-stress performance ideal for urban use, but demands strict timing belt maintenance to prevent engine damage. SAE 10W-30 ACEA A1/A2 oil is recommended to ensure adequate camshaft lubrication, particularly in early production units. Cold-start idling should be minimized to reduce wear during warm-up. The Siemens SIM1K injection system requires periodic injector cleaning to maintain fuel atomization and idle stability. Post-1997 models feature improved cylinder head oiling; pre-1997 engines should be inspected for cam lobe wear per PSA TGB004. The three-way catalytic converter requires unleaded fuel meeting EN 228 standards to prevent poisoning.
Oil Specs: Requires ACEA A1/A2 specification (PSA SIB TGB004). BMW Longlife or VW 502 00 not compatible.
Emissions: Euro 2 certification applies to all K1H (TU3A) models (1993–2001) (VCA Type Approval #VCA/EMS/7890).
Power Ratings: Measured under ECE R85 standards. Output consistent across fuel qualities meeting EN 228 (PSA TIS TU3012).
PSA Technical Information System (TIS): Docs TU3001, TU3012, TGB004
VCA Type Approval Database (VCA/EMS/7890)
ISO 1585:1996 Road vehicles — Engine test code — Net power
The Citroen K1H (TU3A) was used across Citroen's Saxo platform with transverse mounting and shared with Peugeot under PSA platform commonality. This engine received model-specific tuning-for lighter throttle response in the Saxo-and from 1997 the updated cylinder head with revised oil galleries, creating interchange limits. Partnerships within the PSA Group allowed Peugeot's 106 to use identical powertrain calibration. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the transmission bellhousing (PSA TIS TU3005). The 8th VIN digit indicates engine type ('K' for K1H series). Pre-1997 models have a silver cam cover with black intake manifold; post-1997 units use black cam covers. Critical differentiation from TU3J: K1H (TU3A) has Siemens SIM1K ECU with round diagnostic connector, while TU3J uses Magneti Marelli with rectangular port. Service parts require production date verification - timing belts for engines before 03/1997 are incompatible with later revised tensioners (PSA SIB TGB004).
The K1H (TU3A)'s primary reliability risk is premature camshaft wear on early builds, with elevated incidence in high-mileage vehicles. PSA internal reports from 1998 noted a significant number of pre-1997 engines requiring camshaft replacement before 120,000 km, while UK DVSA MOT records show timing belt neglect as a frequent cause of engine failure. Extended service intervals and short-trip driving increase wear risk, making adherence to maintenance schedules critical.
Analysis derived from PSA technical bulletins (1993-2001) and UK DVSA failure statistics (1995-2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN K1H-TU3A.
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